1. Field of the Invention
The present invention relates generally to vehicle occupant restraint systems, and more particularly, to a seat belt restraint system that incorporates an inflatable section into the torso section of the belt.
2. Background of the Invention
Inflatable seat restraint systems have proven to be a dramatic improvement over ordinary three-point seat belts. Unlike ordinary belts, these systems incorporate inflatable restraints that fill with gas immediately upon vehicle impact. The inflatable restraints pretension the systems with a force sufficient to counter body loading, to restrict occupant motion during a crash, and to distribute crash loads over larger occupant surface area, thus minimizing injury.
FIGS. 1a-1e illustrate a typical prior art inflatable seat restraint system, as disclosed in the commonly assigned U.S. Pat. No. 5,839,753 to Yaniv et al., which is incorporated by reference herein. The system includes lap belt 102, shoulder or torso belt 103, including an inflatable restraint 101, buckle assembly 105, anchor 106, anchored inertia reels 117 and 118, gas generator 122, and a sensor assembly (not shown).
As shown in FIG. 1c, lap belt 102 and shoulder belt 103 form one continuous strap which passes through the male portion of buckle assembly 105. Lap belt 102 is designed to restrict the forward motion of a seated occupant at the pelvis. Lap belt 102 is connected to anchored inertia reel 117, which pivotally mounts lap belt 102 to the floor or seat structure on the door-side of seat 121 (as shown in FIGS. 1a and 1b). The other end of lap belt 102 loops through the male portion of buckle assembly 105, so that the length of lap belt 102 can be adjusted to accommodate a wide range of occupant sizes.
The female portion of buckle assembly 105 is attached to buckle strap 107. Buckle strap 107 is pivotally mounted to an attachment point in the vehicle, such as the base of seat 121, or a floor structure on the side of seat 121 that is farthest from the door, by anchor 106. The female and male portions of buckle assembly 105 fasten together, thus securing seat belt system 110 around the occupant in a manner similar to that of conventional three-point seat belt systems.
As shown in FIG. 1d, gas generator 122 is typically mounted inside the seat back. The gas generator is also sometimes located in the seat base. Durable tubing 116 provides a fluid path from gas generator 122 to inflatable restraint 101.
As shown in FIG. 1c, inflatable restraint 101 is attached to shoulder belt 103 and extends diagonally from the occupant""s hip to behind and above the occupant""s shoulder. The upper end of inflatable restraint 101 loops through a D-ring 108 that is mounted to seat 121 as shown (FIG. 1d) or to the vehicle (e.g., at the roof rail or at the upper B-pillar area (not shown)). D-ring 108 acts as an intermediate guide for shoulder belt 103, setting the height at which shoulder belt 103 wraps over the occupant""s shoulder. Shoulder belt 103 is then anchored to seat 121 or the vehicle (not shown) by an inertia reel 118.
As shown in FIG. 1a, shoulder strap 103 is routed inside the vehicle seat to inertia reel 118, which is mounted in the lower portion of the seat back. Thus, as shown in FIGS. 1b and 1d, tubing 116 provides fluid communication from the gas generator to inflatable restraint 101 in the torso of the restraint system.
As best shown in FIG. 1d, when a collision occurs, the crash sensor sends a signal to the initiator in gas generator 122. The initiator then ignites the gas generator 122, which forces gas through durable tubing 116 and into inflatable restraint 101. As the gas flows into inflatable restraint 101, the internal pressure causes the tube diameter to increase and the tube length to decrease. At the same time, seat belt system 110 is constrained on the outboard side by inertia reel 117 and on the inboard side by anchor 106, and behind the shoulder by inertia reel 118. Inertia reels 117 and 118 lock up during impact, preventing payout of the belt. Thus, as inflatable restraint 101 contracts, it pulls any slack out of seat belt system 110. The occupant is thus provided with a pretensioned seat belt, which restricts the forward motion of the occupant and reduces primary injuries.
Typically, conventional inflatable seat belt restraint systems mount inflators in one of two locations: 1) either behind the seat for inflation from behind the occupant and over the shoulder, or 2) at the buckle for inflation from the buckle up to the occupant""s shoulder. The inflatable seat restraint system of FIGS. 1a-1e is an example of this first configuration, which is referred to herein as the shoulder-fill design. The second configuration is referred to herein as the buckle-fill design. As used herein, inflator means any device that fills an inflatable restraint during system deployment, e.g., a gas generator.
For both the shoulder-fill and buckle-fill designs, providing shoulder belt height adjustment to accommodate different torso lengths is a significant concern. To provide maximum occupant protection, the intermediate guide for the shoulder belt (e.g., D-ring 108 in FIGS. 1a-1e) must not be below or too far above the occupant""s shoulder. Indeed, most manufacturers and safety experts recommend that the intermediate guide be positioned at or above an occupant""s shoulder, with a maximum shoulder belt angle of 30xc2x0 above horizontal. Such shoulder belt height adjustments are simple for conventional three-point seat belt systems, which have no inflatable restraints. However, substantial difficulties arise when incorporating sections of inflatable restraint.
For example, shoulder-fill designs, such as the design illustrated in FIGS. 1a-1e, mount the inflator in a fixed position and use a high-pressure hose to connect the inflator to the inflatable restraint. The high-pressure hose is flexible to accommodate shoulder belt height adjustments, e.g., when D-ring 108 is raised to wrap the belt over an occupant with a longer torso. Although this shoulder-fill design permits moderate shoulder belt height adjustment, the inflatable restraint must pass through the intermediate guide. Because the inflatable restraint tends to be bulky and stiff, the inflatable restraint and the webbing to which it is attached often kink and bunch around the intermediate guide. In addition, the small diameter of a typical intermediate guide (e.g., a D-ring) pinches the inflatable restraint and webbing. These restrictions cause uneven travel and deployment of the inflatable restraint, resulting in inadequate occupant protection. Although providing stronger clock springs on the inertia reel that feeds the webbing may help force the inflatable restraint over the intermediate guide and reduce kinking and bunching, the stronger pull compromises occupant comfort.
In an attempt to accommodate different height adjustments, designers have proposed various modifications to the shoulder-fill design, each with significant drawbacks. Such modifications have included inflators attached directly to the webbing, inflators mounted on linear slides or guides, and inflators mounted on swing arm devices. In providing a degree of shoulder belt height adjustment, each modification compromises occupant comfort or safety in some way. For example, in the systems that move the inflator in concert with the movement of the inflatable restraint, difficulty in sliding or translating the inflator is a common problem.
In addition, shoulder-fill systems that attach the inflator directly to the webbing encounter undesirably high inertial loading during webbing retraction and payout, and during crash events. Installing counterweights and springs can offset this high inertial loading, but requires more parts, increased complexity, and higher costs.
Shoulder-fill systems that mount the inflator on a linear slide can reduce sliding friction. However, these designs also suffer from the undesirably high inertial loading described above.
Shoulder-fill systems that mount the inflator to a swing arm also experience undesirably high inertial loading, unless the inflator is connected through a fluid coupler that pivots about the axis of rotation of the swing arm. However, again, installing the fluid coupler increases the cost and complexity of the system.
All of the modified shoulder-fill designs require some provision for stopping the inertial loads of the inflator in the event of a crash. The webbing feels cumbersome to the occupant due to the inertial loading of the translating inflator. Thus, the conventional shoulder-fill designs fail to provide an optimal solution.
Buckle-fill designs suffer from drawbacks as well. For example, a typical buckle-fill design fixes the inflatable restraint at the buckle where the gas is injected. An inertia reel mounted behind the seat lets out and retracts the webbing to accommodate the raising and lowering of the intermediate guide for shoulder belt height adjustment. Because this design requires that the inflatable restraint be fixed at the buckle, the length of the inflatable restraint remains unchanged as the intermediate guide is raised. Thus, when the intermediate guide is raised to its highest point, the inflatable restraint may not reach the shoulder of an occupant with a longer torso, therefore compromising occupant protection in this area.
To provide inflatable restraint protection in this unprotected area, the design could extend the inflatable restraint up to the intermediate guide for the occupant with a longer torso. However, when the intermediate guide is lowered for smaller occupants, the inflatable restraint would have to pass through the intermediate guide, thereby raising the same problems discussed above for shoulder-fill designs (i.e., uneven travel and deployment due to kinking, bunching, and pinching).
In addition to inadequate shoulder belt height adjustment, the shoulder-fill and buckle-fill designs require a large number of components and several complex connections. For example, both designs necessitate a separate inflator housing and the shoulder-belt design requires large amounts of expensive high-pressure hose to connect the inflator to the inflatable tubular structure. In addition, the designs rely on conventional inertia reels, which are not designed for inflatable seat belt restraint systems and therefore can often be unreliable.
The present invention is an inflatable seat belt restraint system, and a corresponding method for deploying an inflatable seat belt restraint, which use an inflation integrated inertia reel to provide a wide range of shoulder belt adjustment. The inflation integrated inertia reel mounts above an occupant""s shoulder and secures both the shoulder belt webbing and inflatable restraint of the restraint system. An inflator in fluid communication with the inflation integrated inertia reel generates pressurized gas that flows into the inflation integrated inertia reel and then into the inflatable restraint. The pressurized gas can also be used to positively lock up the inflation integrated inertia reel.
In mounting the inflation integrated inertia reel above the occupant""s shoulder, the present invention eliminates the need for an intermediate guide and thereby solves the problems associated with the bunching and kinking of the inflatable restraints. In addition, by combining the inflator housing and inertia reel into a single component, the present invention uses fewer parts than prior art systems. Thus, the present invention provides shoulder belt adjustment with a minimum number of parts and without sacrificing full inflatable restraint protection from an occupant""s lap to his shoulder.
In an embodiment of the present invention, the inflatable seat restraint system includes a shoulder belt, an inflatable restraint, an inflator, an inflation integrated inertia reel, and a shoulder belt anchor that opposes the inflation integrated inertia reel. The shoulder belt anchor is preferably a buckle assembly. A lap belt and lap belt inertia reel can also be included to provide full occupant protection. The buckle assembly and lap belt inertia reel are attached to a lower portion of a seat or to a vehicle structure below the seat, and are located on opposite sides of the seat. The inflation integrated inertia reel is attached to an upper portion of the seat or to a vehicle structure proximate to the seat. The lap belt attaches to the lap belt inertia reel and the buckle assembly across an occupant""s pelvis. The shoulder belt attaches to the buckle assembly and the inflation integrated inertia reel, and spans the occupant""s torso diagonally from shoulder to pelvis. Optionally, the shoulder belt and lap belt could be one continuous belt.
The inflation integrated inertia reel provides several functions of the present invention, including shoulder belt adjustment, gas generation, and the spooling, retracting, and locking of the shoulder belt webbing and inflatable restraint. According to an embodiment of the present invention, the inflation integrated inertia reel includes a webbing anchor, a drum, and a port for ducting the inflation gas to the inflatable restraint. Optionally, the inflation integrated inertia reel also includes a locking mechanism that detects a crash event and locks the drum.
The webbing anchor secures the shoulder belt to the drum of the inflation integrated inertia reel. The port is adapted to fluidly connect an inflatable restraint to the drum and is positioned on the drum beyond the webbing anchor, so that the inflatable restraint lies on top of the webbing of the shoulder belt when the drum spools up. The drum includes a pressure vessel that contains gases generated by an inflator so that the gases are directed out of the port to fill the inflatable restraint. The inflator is in fluid communication with drum, and is preferably located inside the drum. Thus, in effect, the drum of the inflation integrated inertia reel acts as the inflator housing, holding the inflator and ducting the discharged gas into the inflatable restraint.
In operation, the drum of the inflation integrated inertia reel rotates to take up and pay out the shoulder belt webbing and the inflatable restraint spooled around it. The rotation allows an occupant to adjust both the tightness of the shoulder belt against his body and the height of the inflation integrated inertia reel. As the occupant pulls on the shoulder belt or raises the inflation integrated inertia reel, the drum rotates to pay out additional lengths of webbing and inflatable restraint. Thus, at any point in its rotation, the inflation integrated inertia reel can deliver an unimpeded charge of gas from inside the drum to the inflatable restraint.
In an embodiment of the present invention, the drum includes a locking mechanism that activates (i.e., stops the drum from rotating) when the drum is pressurized. Thus, during deployment, the gas not only fills the inflatable restraint, but also fills the drum and stops the drum from rotating. The locked drum then restrains the webbing of the shoulder belt and the inflatable restraint, preventing further payout.
In another embodiment of the present invention, the drum is shaped to raise and lower the shoulder belt height as the drum rotates.
In another embodiment of the present invention, a lever arm and stop are added to the inflation integrated inertia reel to provide both shoulder belt height adjustment and shoulder belt length adjustment.
Accordingly, an object of the present invention is to maximize the protection provided by inflatable seat belt restraint systems for occupants of all sizes.
Another object of the present invention is to provide an inflatable seat belt restraint system that provides shoulder belt height and length adjustment.
Another object of the present invention is to provide an inflatable seat belt restraint system that locks up an inertia reel more quickly than conventional inertia reel locking mechanisms.
Another object of the present invention is to reduce the number of components required to provide an inflatable seat belt restraint system with shoulder belt height adjustment.
These and other objects and advantages of the present invention are described in greater detail in the detailed description of the invention, and the appended drawings. Additional features and advantages of the invention will be set forth in the description that follows, will be apparent from the description, or may be learned by practicing the invention.